"These birds are free, no strings attached. I don't know what's going to happen either," Ms Stewart told the visitors.
"They may chase things and that's normal behaviour."
Wingspan has a museum and an aviary for visitors to wander around. Inside the aviaries are morepork, Tahi - an Australasian barn owl - karearea (the NZ falcon) and Australasian harrier hawks.
"Rotorua people forget how significant Rotorua is to significant conservation programmes throughout New Zealand," Ms Stewart said.
"We have karearea, kiwi, kokako. We're all about being kaitiaki [guardians]. We can be proud of that without question. We're proud to be Rotorua-based and we still get people discovering us for the first time. We're not a tourist attraction but an active conservation programme that people can visit."
She said 32,000 children had held karearea over the 21 years Wingspan had been open.
"We try to let everyone who wants to have a hold, have a hold. They're not going to forget that."
The Rotorua Daily Post Essential 50 lists the city's must-see, must-do and must-try activities and experiences thanks to reader nominations. We'll be highlighting one every day over summer.